Conventionally, in dicing a semiconductor wafer on which a circuit surface is formed, the semiconductor wafer is disposed in an inside area of a ring frame, and a dicing tape is stuck on the surface thereof to fix the semiconductor wafer to the ring frame. As for sticking of the dicing tape, the method is known in which after sticking a continuous dicing tape of a strip shape to the ring frame and the semiconductor wafer, a peripheral side of the dicing tape is cut off in accordance with the shape of the ring frame with a cutter.
As another sticking method, for example, as disclosed in a Patent Document 1, there has been employed a method in which, using a rolled raw sheet having label-like dicing tapes formed thereon, which are previously provided with a cut on the surface of the film in accordance with the shape of the ring frame, the dicing tapes are peeled off one by one in the process of feeding out the raw sheet and stuck onto the ring frame.
[Patent Document 1] Japanese Patent Application Laid-open No. Hei 6-216242
However, in the former method in which, after a dicing tape continuing in a strip shape is stuck, a peripheral side of the tape is cut off with a cutter in accordance with the shape of the ring frame, there resides such a disadvantage that the ring frame is considerably damaged by the cutter blade since the dicing tape is cut off within a surface of the ring frame. Particularly, in the case where a resin ring frame is used to achieve low manufacturing cost and weight reduction, the degree of the damage is further considerable. Moreover, the refuse of the tape cut off with the cutter comes to considerable amount, which results in a disadvantage of wasteful material consumption and economical burden.
On the other hand, as disclosed in the Patent Document 1, in such a method that a dicing tape previously cut in a shape of the ring frame is stuck, a different process to form dicing tapes of a label-like shape in the surface of the film is required. In addition, when a material of tape base is rigid and thick, there is such a disadvantage that the tape base is peeled off from a base sheet during feeding out. Further, the dicing tape with the cut of the label shape formed thereon is wound in a roll-like shape in a state that the dicing tape is stuck to the base sheet via adhesive. Therefore, the dicing tape is not wound always in such a state that the dicing tapes in each layer along the diameter direction of the roll are precisely overlapped with each other. As a result, due to an elastic deformation of the adhesive and edges of the dicing tapes overlapping with each other, a press-trace (step) or a press-damage due to the winding pressure is formed in the surface of the dicing tape, resulting in a serious deterioration of the plane accuracy. When the dicing tape having such press-trace or press-damage is stuck to the ring frame, it may cause a problem of aeration and the like due to deteriorated plane accuracy, which can be a cause of sticking failure or the like.
The present invention has been proposed in view of the above disadvantages. It is an object of the present invention to provide a mounting apparatus and a mounting method capable of forming dicing tapes in a predetermined shape in the process of feeding out a strip material while sticking the dicing tape to a semiconductor wafer and a ring frame immediately after the tape is formed, and thereby eliminating cutting process with a cutter after sticking the dicing tape.
Another object of the present invention is to provide a mounting apparatus and a mounting method capable of preventing the conventional problems due to the winding pressure, thereby increasing a sticking accuracy.
To achieve the objects, an apparatus according to the present invention employs an arrangement such that a mounting apparatus for fixing a semiconductor wafer to a ring frame by sticking a dicing tape to the ring frame in a state that the semiconductor wafer is disposed in an inside area of the ring frame disposed on a table, the apparatus includes:
a supporting means for supporting a strip material attaching a film for forming dicing tapes stuck on one surface of a base sheet;
a pre-cut means for forming a dicing tape by forming a cut in the film in accordance with the size of the ring frame; and
a sticking means for fixing the semiconductor wafer to the ring frame by peeling off the dicing tape from the base sheet and sticking the dicing tape onto the ring frame.
In the mounting apparatus, it is preferable that a tension control means be disposed between the supporting means and a pre-cut means, the tension control means including: a dancer roller which is movable vertically so as to allow the strip material to be fed out toward the sticking means while giving tension due to its own weight to the strip material; and first and second sensors for detecting a raised position and a lowered position of the dancer roller, respectively, wherein,
when the first sensor detects the dancer roller at the raised position, the supporting means feeds out the strip material by a predetermined amount to lower the dancer roller; and wherein, when the second sensor detects the dancer roller at the lowered position, the supporting means stops feeding out the strip material therefrom.
Further, a method according to the present invention is a mounting method in which a ring frame is disposed on a table while a semiconductor wafer is disposed in an inside area of the ring frame, and a dicing tape is stuck onto the ring frame to fix a semiconductor wafer to the ring frame, the method including the steps of:
forming a cut in a film in accordance with the size of the ring frame in the process of feeding out a strip material attaching the film for forming dicing tapes stuck on one surface of a base sheet;
peeling off the dicing tape formed inside the cut from the base sheet; and
moving the dicing tape and the table relative to each other to stick the dicing tape onto the semiconductor wafer and the ring frame, thereby fixing the semiconductor wafer to the ring frame.
In the method, it is preferable that a tension control means be disposed between the supporting means and a pre-cut means, the tension control means including: a dancer roller which is movable vertically so as to allow the strip material to be fed out toward the sticking means while giving tension due to its own weight to the strip material, and first and second sensors for detecting a raised position and a lowered position of the dancer roller, wherein,
the following operations are repeated; i.e., when the first sensor detects the dancer roller at the raised position, the supporting means feeds out the strip material of a predetermined amount to lower the dancer roller, and when the second sensor detects the dancer roller at the lowered position, the supporting means stops feeding out the strip material therefrom.
According to the present invention, a strip material is formed in a state that a film for forming a dicing tape is stuck to a base sheet, and the strip material is fed out from a state being wound in a roll-like shape. In the strip material fed out, a pre-cut means forms a cut at a position on the way of feeding so as to have a plane configuration corresponding to the shape of the ring frame and the dicing tape is formed in an inside area enclosed by the cut line. The dicing tape is, for example, peeled off via a peel plate or the like, and then stuck to the ring frame and the semiconductor wafer. Therefore, a process to cut a film on a ring frame after sticking is not required; thus, the ring frame is prevented from being damaged. Further, since the dicing tapes are formed in the feed-out process from the rolled raw sheet, the dicing tapes are prevented from forming press-trace, press-damage or the like due to the aforementioned winding pressure. Owing to this, the dicing tape can be stuck to the semiconductor wafer and the ring frame in a state that plane accuracy is maintained with high accuracy.
Furthermore, since the tension control means are provided, the tension to the strip material can be always maintained at a constant level, and the sticking position of the dicing tape after the pre-cutting can be maintained with a high accuracy.